Establishing a program to trade nitrogen and phosphorous credits among wastewater dischargers is premature without numbers stating what the limits are for those nutrients in Arkansas waters, commenters on a proposed state regulation said.

The complaint -- and many others -- is the same as six months ago, when people first had an opportunity to comment on an earlier draft of the same proposed regulation. Two dozen people or organizations submitted feedback the second time.

Four cities in Northwest Arkansas -- Bentonville, Fayetteville, Rogers and Springdale -- are petitioning environmental regulators to establish a program that allows entities with wastewater discharge permits to avoid exceeding their permit limits by trading with other entities for more wiggle room.

"Nutrient trading," as it's called, allows someone who is below his permit limits for phosphorus and nitrogen to trade the excess allowance permitted to someone else who is above his permit limits or concerned about being above them. Under the proposal, the trades must result in a net reduction of those nutrients being discharged or "loaded" into the water.

In Northwest Arkansas, discharge limits related to a nutrient crackdown in the Illinois River watershed have caused five wastewater treatment plants' permits to be placed on indefinite hold while the utilities find a way to comply. The utilities' permits remain active, despite expiring years ago, under Arkansas Department of Environmental Quality administrative continuances.